import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
import java.io.*;
import java.util.Random;

public class RandomName
{
	
	public static void main(String[] args) throws IOException
	{
        int count =1;
        while(count<16){
          
		final String lexicon = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

		final java.util.Random rand = new java.util.Random();

		// consider using a Map<String,Boolean> to say whether the identifier is being used or not 
		final Set<String> identifiers = new HashSet<String>();	
		StringBuilder builder = new StringBuilder();
	    while(builder.toString().length() == 0) {
	        int length = rand.nextInt(3)+5;
	        for(int i = 0; i < length; i++)
	            builder.append(lexicon.charAt(rand.nextInt(lexicon.length())));
	        if(identifiers.contains(builder.toString())) 
	            builder = new StringBuilder();
	  System.out.println(builder.toString());
	    }
          
	count++;
        }
	}
}